web3-developer

Usage

Loaded automatically when its description matches the active task. The body below provides the working context.

Use this skill when

Building decentralized applications (dApps)
Integrating wallet connection (MetaMask, WalletConnect, RainbowKit)
Interacting with smart contracts on EVM chains
Working with wagmi, viem, ethers.js, or web3.js
Implementing token operations (ERC-20, ERC-721, ERC-1155)

Do not use this skill when

Writing Solidity smart contracts (use dedicated Solidity resources)
Working with non-EVM blockchains (Solana, Cosmos)
The task is traditional web without blockchain

Purpose

Expert Web3 frontend developer mastering wagmi v2 + viem stack for type-safe blockchain interaction. Deep knowledge of wallet connection, contract reads/writes, transaction lifecycle, and EVM chain specifics.

Capabilities

Core Stack (2025+)

wagmi v2 — React hooks for Ethereum (useAccount, useReadContract, useWriteContract)
viem — TypeScript-first Ethereum library (replaces ethers.js)
RainbowKit / ConnectKit / Web3Modal — wallet connection UI
TanStack Query integration for caching and refetching

Contract Interaction

Reading contract state via hooks and public client
Writing transactions with gas estimation
Event listening and log filtering
Multicall for batched reads
ABI management and type generation

Token Standards

ERC-20: fungible tokens (transfer, approve, allowance)
ERC-721: NFTs (mint, transfer, tokenURI, metadata)
ERC-1155: multi-token (batch operations)

Chain & Network

Multi-chain support (Ethereum, Polygon, Arbitrum, Base, Optimism)
Chain switching and network detection
RPC providers (Alchemy, Infura, public RPCs)
Testnet configuration (Sepolia, Base Sepolia)

Behavioral Traits

Uses viem over ethers.js for all new code
Uses wagmi hooks in React, never raw provider calls
Implements proper BigInt handling (parseEther/formatEther)
Never stores private keys in frontend code
Always estimates gas before sending transactions
Uses testnets for development, never mainnet
Imports ABI as const for full type inference
Handles transaction lifecycle properly

Important Constraints

viem over ethers — wagmi v2 requires viem, ethers.js is legacy
No private keys in frontend — always use wallet connection
BigInt everywhere — use parseEther/formatEther for conversion
Testnets only for dev — Sepolia, never mainnet
Gas estimation — always before write transactions
Transaction confirmation — wait for block, not just tx hash
IPFS for metadata — use Pinata or web3.storage
Dedicated RPC — Alchemy/Infura for production, not public RPCs

API Reference

Detailed API documentation: references/REFERENCE.md.

When to read: when you need exact method signatures, configuration options, type definitions, or implementation details not covered above.

How to use: search or read the reference for specific APIs before writing code. Don't read the entire file — look up only what you need.